[Inflammatory hypertrophic cranial pachymeningitis].

DEFINITION: Inflammatory cranial hypertrophic pachymeningitis (ICHP) is a fibrosing inflammatory process that thickens the dura mater. This condition is increasingly reported owing to the use of CT and MRI. CLINICAL ASPECTS: Chronic headache and cranial neuropathies are the main presentations. Generally the erythrocyte sedimentation rate is elevated and cerebrospinal fluid is inflammatory. DIAGNOSIS: Non-invasive imagery visualizes the thickening of the dura mater that may be focal or diffuse. On MRI diffuse intense enhancement due to intra cranial hypotension must not be confused with ICHP. Focal thickening of the dura may be tumoral. Biopsy of the thickened dura mater is useful for confirming the inflammatory nature of the process and for orienting the etiological diagnosis. "SECONDARY" ICHP: ICHP has many causes, infectious and noninfectious. It may be the presenting manifestation of systemic diseases as sarcoïdosis or Wegener's granulomatosis. "IDIOPATHIC" ICHP: A diagnosis of exclusion, ICHP might be an isolated intracranial localization of multifocal fibrosis, an ill-defined autoimmune disease. TREATMENT: A specific treatment is indicated in some cases of secondary ICHP. In most cases treatment relies on corticosteroids an/or immunosuppressive therapy.